Governor



Apr. 3, 1923. 1,450,380.

A. F. MEYER.

GOVERNOR.

FILED MAR. 29, 1920- 4 S HEETSSHEET I.

2 F y 37 E 3? [/2 Vent or 17001 P [7715 02 fiz's Aor-re e505.

4 SHEETS-SHEET 2.

A. F. MEYER.

GOVERNOR.

FILED MAR.29, 1 920.

Apr. 3, 1923.

H w xi Apr. 3, 1923. 1,450,380. A. F. MEYER.

GOVERNOR.

FILED MAR. 29. 1920. 4 SHEETS-SHEET 3.

Apr. 3, 1923. 1,450,380. A. F. MEYER.

GOVERNOR.

FILED MAR. 29. 1920. 4 SHEETSPSHEET 4.

[7'2 aerator 15 004 PHFME r512 15 21916 (for): eys.

Patented Apr. 3, 1923.

ADOLPH F. MEYER, OF ST. PAUL, MINNESOTA.

GOVERNOR.

Application filed March 29, 1920. Serial No. 369,804.

To all whom it may concern:

Be it known that I, ADoLPH F. MEYER. a citizen of the United States, resident of St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements inGovernors, of which the following is a specification.

This invention relates to a new and improved governor for the control of fluid flow and pressure. It is particularly adapted for use as a means for the automatic maintenance of a desired speed of rotation of a driven member working under a frictlon load produced by fluid pressure. This governor is capable of a wide variety of uses in which a sensitive and responsive automatic control of fiuid pressure and flo-w is desired. In the selected embodiment of the invention herein disclosed,-this novel governor is shown as adapted for use in the wood-pulp making art. It is particularly adapted for use in connection with the wellknown hydraulic turbine driven grindstones used for the production of wood-pulp.

In this art, as at present practiced, turbogrinders are employed which have a plurality of what are termed pockets into which wood blocks are placed and are pressed by hydraulic means against the face of the rotating grindstones. At present when the blocks in one pocket are completely ground or the pocket is pulled off for refilling with wood, the normal friction load on the turbogrinder is resultantly lessened and the turbogrinder speeds up, causing a loss of power through reduced efiiciency of the hydraulic turbine. In fact the speed of the turbogrinders at present is continually varying as the friction load changes with. the number of pockets in use, the size and character of wood ground and the arching and binding of the wood in the pockets. By means of the invention here disclosed it is possible to maintain any desired speed of rotation of the turbo-grinder and thus to prevent loss of power.

This novel and improved governor isentirely automatic in action. It always increases the ressure with the least increase in speed of the turbo-grinder, and decreases" it with the least decrease in speed. The forces employed in the device are in equilibrium, that is, ina state of rest,- only when the speed is normal. In consequence, it is poss ble to make the present governor as sensltive as practical considerations dictate.

In view of the large amount of power apphed to the turbo-grinder shaft, and the small fly-wheel efi'ect secured from the turbine-runners and the grindstones themselves, a cond tion is imposed which makes good governing an extremely difiicult operation. Large speed variations occur normally in from one to two seconds, varying with conditions in individual mills. To help overcome any existing tendency towards hunting an adjustable by-pass has been provided by means of which a steady friction load is applied to the grindstones irrespective of the action of the governor valve. In other words, good governing is accomplished through the employment of a practically uniform resistance to fiow through the by-pass, plus a variable resistance ap plied through the governor valves, the result of course being a variable pressure in the grinder pockets as demanded by the conditions prevailing. In this wayan extremely sensitive governor is provided that acts instantaneously, anticipates large speed changes by its rapid motion, and thus produces sensibly constant speed of rotation of the turbo-grinder.

An object of the invention, therefore. is to provide an improved device for controlling fluid pressure.

more specific object is to provide a means for the automatic maintenance of a desired speed of rotation of a driven member working under a friction load produced by fluid pressure.

Other objects of the invention will more fully appear from the following description and the accompanying drawings and will be pointed out in the annexed claims.

In the accompanying drawings, there has been disclosed a structure designed to carry out the objects of the invention, but-it is to be understood that the invention is not to be confined to the exact features shown, as various changes may be made within the scope of the claims which follow.

In the drawings:

Figure 1 is a vertical sectional view through the valve structure, with the valve in the automatic stop position;

'head movable in a cylinder.

is a section on the line H of structure combined with a grinder.

In the preferred embodiment of this invention this means for the automatic maintenance of a desired speed of rotation, is shown in connection with a driven member such as a grindstone. A plurality of these\ grindstones are usually mounted upon and rotated by a driven shaft. An instrumentality is provided to press wood placed in pockets against the face of the grindstones, and usually consists of a piston having a The opposite end of the iston is provided with a foot by means of w ich the wood is pressed against the grindstone face. It is to be understood that, not only may a plurality of these grindstones be mounted upon a shaft, but each grindstone may be rovided with more than one of these cylin ers and piston devices for pressing the wood in the several pockets against the grindstone. The grindstone is thus operated under friction load induced by sticks of wood thus forcibly held against its peripheral surface.

It is customary in this art to drive these grinders by hydraulic turbine means. Such turbo-grinders have an efiicient speed of rotation for any given condition and it is forthe maintenance of this eflicient speed 'of rotation that the structure here disclosed is employed. It is also common in this art to employ a fluid under pressure not only for the purpose of forcibly pressin the wood in the pockets against the grin er by means of the piston, but also to use this fluid pressure to force th piston head away from the grindstone in order that the pockets may be refilled. It should be noted that the maintenance or governing of the speed of rotation of these turbo-grinders is effected by the maintenance of a uniform friction load. For example, when one pocket is pulled off for refilling it is obvious that the grinder would tend to speed up due to lessened load, hence the pressure must be increased upon the other pistons. A complication arises in that the amount of fluid, such as water, consumed in forcing the pistons in their normal working movement to maintain objects engaged with the grinder, is small; while the amount of water consumed upon abnormal movement of each piston from or to its objectmaintaining position is relatively large. These two factors have heretofore been insurmountable obstacles to the eflicient speed governing of the grinders. The novel structure here disclosed employs two co-operat- ,seo

ing mechanisms, which control the pressure supplied to the pistons. Oneof the mechanisms is actuated by changes in the speed of rotation in the turbo-grinder and t e other is actuated by changes in the flow of water to the cylinders and pistons. Only the latter mechanism is directly actuated by the abnormal movement of the piston. The former is indirectly actuated if such abnormal movement causes speed changes. In order to prevent speed changes it is hi hly desirable that increased flow resulting rom abnormal movement shall not cause a pressure drop in th cylinders which are pressing wood against the grindstone. In other words, variations in pressure resulting from variations in water flow through the supply pass must be prevented. This novel structure effects such result through the co-operation of the two mechanisms.

The selected embodiment of this invention in combination with such a turbo-grinder is diagrammatically shown in Figure 5.. The grindstone 1 is fast upon the turbine-driven shaft 2. A cylinder 3 is suitably mounted adjacent the peripheral surfaces of the grindstone and bears therein a piston-head mounted upon the rod 5-, the opposite end of which carries a foot 6, operating in the pocket 7 to press objects, such as blocks of wood, against the surface of the grindstone, whereby the wood is ground into pulp. It is necessary for the purpose of disclosure of this invention only to show one cylinder and pocket and grinder, but it should be noted that the grinders are usually employed in a series fast on the same driven shaft and, furthermore, that a plurality of similar pockets and wood-pressing means are used in conjunction with each grinder.

A pass isprovided which is adapted to supply a fluid, such as water, under pressure from a suitable source, to the wood-pressing cylinders. Herein such pass is shown as comprising a supply pipe 8 connected to a suitable source of supply of water under pressure, and having the valve mechanism interposed in the supply pass between the pipe 8 and the pipe 9, which forms a continuation of the pass. This pipe 9 supplies the water under pressure in accordance with usual practice to each of the different pocket cylinders. As shown in Figure 5, a passage 10 is shown as leading from the pipe 9. This passage is provided with a two-way valve 11 diagrammatically represented, which is manually operable either to divert the water under pressure to one side of the piston head wardly forced to maintain the wood in en gagement with the grindstone. This movement is termed, for the sake of brevity, the normal movement. As the piston head 4 is downwardly forced by means of pressure admitted to the upper portion of the cylinder through the port 12, any water in the lower .portion of the cylinder may escape through the port 13 by way of the two-way valve 11 through the exhaust 14. The socalled abnormal movement of this woodfeeding instrumentality occurs when the valve 11 is manually turned half-way so that direct connection is had between the port 12 of the cylinder and the exhaust 14 to permit escape of the water from the upper portion of the cylinder and to direct the water under pressure from the passage 10 to the port 13 whereby the piston-head 4 is upwardly forced to permit refilling of the pocket with wood. This abnormal movement, being substantially unopposed is relatively rapid and demands a relatively increased amount of water.

This novel speed-governing means involves the co-operation of two devices which in this preferred embodiment of the invention are disclosed as valve mechanisms. The one mechanism functions principally to increase the friction load upon the grinder whenever the grinder tends to increase its speed of rotation over its desired eflicient rate. Such valve mechanism consists broadly of an element rotatively driven by the grinder shaft and adapted to produce fluid pressure on one side of a partitioned chamber, variable in proportion to the speed of rotation of the grinder shaft. This pressure strains to move the partition against, and in an opposite direction to, a straining force exerted on the other side of this chamber partition. This chamber partition may be provided by means of a cylinder and piston structure broadly like the cylinder 3 divided into compartments by the piston 4:, but in this preferred form is provided by means of a diaphragm extending across the pressure chamber and connected to a valve, which is movable to control the pressure under which the water is supplied to the pockets through the above-mentioned supply pass. The valve is operatively connected to this diaphragm and is moved thereby. There is a means straining to move the valve, via the diaphragm, in one direction. Such means is preferably elastic and is here shown as a spring, the straining force of which is preferably adjustable by which means the device may be set for operation to maintain any desired speed of grinder rotation. The grinderdriven rotary element maintains a pressure on the other side of the diaphragm which strains to move the valve in an opposite direction. The variations in the straining pressure, induced by the impeller, function to determine the direction and extent of valve movement which in turn controls the 1ncrease or decrease of pressuresupplied to the pockets through the water supply pass.

The supply water under pressure enters the valve structure through the port 16 and finds an outlet through the section 17 of the pass. The valve structure includes a pressure chamber 18 provided by the'casting 19. The casting 19 is also formed with a central wall 20 which directs the water above and below this wall through the passages 21, into the pressure chamber 18. A substantially annular water-way 22 receives water from the chamber 18 and delivers it to the main section 23 through which the water may travel to the gradually contracted section 15 of the supply pass and thereafter travel to the pipe 9 for delivery to the various passages 10 leading to the cylinders 3 of the pockets 7. It may be noted at this point that, as shown in Figure 3, a by-pass is provided around the valve mechanism. This by-pass 25 is provided with pipe-sections suitably coupled and secured to the casting 19 so that water may flow from the port 16 directly to the supply pass on the other side of the valve chamber. The water pressure communicable through this by-pass is variable by means of the manually operable valve 26. The function of this by-pass is to provide a relatively constant flow of water under pressure to the cylinder pistons. This'flow is a substantial part of the normal grinding requirement, but only a minor part of the total flow which must be supplied during abnormal refilling movement of the pistons.

For purposes of facility in description, one of the two co-operating valve-s shown may be termed the upper and; the other may be termed the lower valve, although it is to be understood that the valve mechanisms function in other positions.

The upper valve is preferably of the skeleton type and consists of an annular ring portion 27 carried by a plurality of arms or bridges 28 preferably integral with the valve stem 29. Water may, therefore, circulate freely through the valve, finding outlet through the annular opening 30 intothe waterway 22 and thence to the supply passleadingto the pockets. A bushing 32 is provided on the casting 19 adjacent the annular opening 30 against which the inner face of this annular valve portion 27 is slidably engageable. This valve is movably mounted to control the pressure under which the water is supplied to the pockets to produce the friction load on the driven grinders. In this preferred construction, the valve is influenced by elastic means straining to move the valve in one direction and by another means actuated by the driven grinder member straining to move the valve in an opposite direction. The elastic means is adjust-able to be set at a predetermined point and furnishes a relatively constant straining effort which is opposed by the variable effort of the other means. Several different elastic means may be employed for this purpose and, in this embodiment, it is disclosed asa spring 33 mounted in the frame 34 suitably bolted to the housing. The valve stem 29 upwardly projects and is terminally engaged by a block 35 which substantially forms therewith a ball and socket connection. The lower end of the spring 33 rests upon the opposite face of this block 35 while the upper end of the spring is heldvby the block 36. This upper block has a substantially ball and socket connection with the threaded bolt 37 adapted to be manually turned, in its threaded engagement with the head 38 of the frames 34, by means of the hand-wheel 39. Upon thev rotation of this hand-wheel, the tension of the spring, exerting a downward thrust or spring effort on the valve, may be adjustably varied.

The valve, as above noted, is also acted upon by fluid means straining to move the valve in an opposite direction. This fluid means is co-operable with a rotatory element, which is actuated by the driven rinder shaft. The valve stem 29 has ap ate 40 secured thereto, the upper face of which abuts against the under face of the diaphragm 41 of suitably flexible mater1al such as a rubber composition. The peripheral portions of this diaphragm are securely held between the chamber housing. or casting 46 and the annular plate 42, bolted to the housing. Acap 43 is keyed to the valve stem 29 and is downwardly pressed by means of the adjustable nut 44 received in threaded engagement on the terminal portion of the valve stem 29, securely to hold the diaphragm on the valve stem so that movement of the diaphragm will cause movement of the valve stem. This diaphragm functions as the cover of a pressure chamber 45, the other sides of which are provided by the housing preferably formed by a casting 46 secured by a plurality of bolts 47 to the casting 19 of the waterway housing.

This pressure chamber 45 is filled with a fluid such as water, the pressure of which is caused to vary in proportion with the speed of rotation of the grinder shaft, by means ofa centrifugal pump typeof impeller. This impeller is provided with a housing 50 which upwardly provides a water reservoir 51. The impeller housing is secured to the casting 46 by means of bolts 52. The impeller is provided with a stem 53 rotatably mounted in the housing 50 and having suitably packed hearings to prevent escape of the water. The stem carries a disk 54 hearing radially projecting vanes 55. An annular way within which the disk and vanes rotate is provided by the casting portion 49.' A peripheral end portion of the way is provided with an annular passage 56 which, on the side adjacent the pressure chamber 45, communicates with a port 57 leading to the pressure chamber. The function of this impeller is to create pressure. There is merely intermittent, slight flow induced by the impeller as the diaphragm 41 moves up or down between the housing 50 and the pressure chamber 45. Since practically all the energy spent in driving the impeller goes intoheat, provision must be made for cooling the circulatin medium. This is accomplished .by 'provi ing small leakage passages between the stem 29 and the bearings therefor in the casting 46, so that the water under relatively high pressure in the pressure chamber 18 can escape in sufiicient' quantity into the pressure chamber 45, and thence through the port 57 into the annular passage 56, and into the overflow reservoir 51, and carry away the heat which may begenerated. This construction eliminates the use of a gland between the pressure chamber 18 and 45 with its accompanying friction loss. It should be noted that successful action of the device is to a degree dependent upon the minimizing of all friction losses, so that the slightest speed change in the grinder shaft will cause motion of this valve. The simple means as here disclosed for actuating the rotatory impeller element by the driven member, consistsin the provision of a beveled gear 59 fast on the lower end of the stem 53, which is in mesh with the gear 60 provided on a countershaft 70, which is rotatably driven by a belt or chain 71in turn driven by a split or sprocket pulley 72- fast on the driven grinder shaft 2.-'

Briefly, the function of this upper valve mechanism is as follows 'Assuming that the grinder is rotating; at its eflicientspeed un-" der its friction loa'd arising from, grinding the sticks of wood the pocketswhich are" being pressed against the grinder by-mean's of fluid pressure applied to the several pis tons 4. TlllS efiicient speed of rotation causes the impeller-to setup a definite pres-' sure 1n the chamber 45. which strains to hold the upper valve against the adjusted tension of its spring 33 in aposition such, for example, as shown in Figure 2. Under such normal conditions the pressure supply to the pistons 4, through this valve mechanism interposed in the fluid supply pass, is

. substantially constant, a portion of this norits - Under such conditions crease in speed of-the grinder in turn causes mitting increased flow of water to the cyl the co-operating impeller to rotate at a inder upon abnormal movement of a' piston. higher speed and to build up a pressurepro- Broadly considered, such result 1s achieved portionateto the increased speed in the presby the application of the Venturi tube prinsure chamber 45. This increased pressure clple.

raises the valve against the tension of the The second, or lower valve structure. also spring 33, so that there is-less obstruction is mounted for movement to control flow tothe flow of water from the supply pass through the fluid pressure pass. It consists to the pistons and hence the pressure on each of an annular ring portion 73 carried by of the pistons at the pockets is increased and bridges 74 secured to the valve stem 75. the'friction load upon the grinder is thereby This lower 'valve is, therefore, similar to increased, and the speed of the grinder the upper valve and likewise water may cirthereby reduced to substantially its eflicient culate freely through this skeleton valve. 1

rate. An annular bushing 76 is provided on the Provision is made for the accidental intercasting 19 adjacent the annular opening 30 ruption of the impeller functions, such as of the waterway 22. The valve stem 75 is the breaking of the impeller drive, so that secured by means of its opposed plate 77 to the full pressure in the pass is immediately a diaphragm 78. The diaphragm functions applied to the pistons to place a full friction as a moving partition in the pressure comload upon the grinder to cause its stoppage. partment 79. Movement of the partition is this upper valve will imparted to the valve through the stem 75. assume the position shown in' Figure 1 This partition is acted upon, and is movable which has been termed an automatic stop in response to, variations in water pressure position. For example, when the belt 71 on its opposed faces. The motion of this breaks, the impeller ceases its rotation, valve is produced by variations in fluid flow pressure drops in the chamber 45, the spring through the supply pass, and to this end, 33 unopposedly exerts its straining effort the supply pass on' the side of the valve to cause the valve to descend to the position structure which is nearer to the pockets is shown in Figure 1, whereby practically unprovided with a gradually contracted section impeded flow is permitted through the sup- 15 through which the water passes from the 1 a main section 23 to the section 17 of the suphe structure heretofore referred to can ply pass leading to the pipe 9. A passage automatically maintain the desired speed 81 connects themain section 23 with the of rotation of the driven grinders working pressure compartment 79 on one side of the under their friction loads produced by the diaphragm while the passage 82 connects pressure supplied to the pistons under what the gradually contracted section 15 with may be termed normal conditions and also the pressure to considerable extent under what may be other side of the diaphragm. Therefore, termed abnormal conditions described later. variations in pressure in the passages 81 Each piston has a normal forward moveand 82 will cause movement of the valve ment, under the pressure of the water in stem 75. When a pocket is pulled oil for rethe supply pass, forcibly to maintain wood filling, an increasedvfiow of water in the supin engagement with the working inder. ply pass results and the increased flow of compartment 79 on the.

This slow piston displacement in t e normal maintaining movement causes a relatively small flow of water through the supwater from the main section 23 through the gradually contracted section 15 results in the transformation of a portion of the fluid pressure head in the main section 23 into pl pass to the piston cylinders.

Tlowevenit is to be noted that each pisfluid velocity head in the contracted section ton also has, what may be termed, abnormal 15, and the attendant drop in pressure in the movements. These abnormal movements passage'82 below that in the passage 81 will are attendant upon the manual operation cause the diaphragm 78 to be downwardly of the valve 11 upon exhaustion of the pressed and hence move the valve portion 73 wood in the pockets, and are to and from to permit increased volume of water to flow the maintaining position. Such movements throu h the pass. Preferably the compartare necessary in refilling the exhausted ment 79 is provided with aprojection 83. A pockets. These movements being unopspring 84 is mounted therein and has one posed, are relatively rapid and entail sudterminal portion in engagement with one of den large flows of water from the supply the plates 77 of the valve stem. The other pass to the cylinders. Such increased flow terminal portion of the spring is seated on of water would naturally cause reduction in the head of a screw 85 received in threaded pressure in the supply pass due to increased engagement in the projection 83. The friction loss at the higher velocities of spring is, therefore, provided with an adflow. The function of the second or lower justable mounting so that the upward thrust valve mechanism is to prevent such presof the spring on the valve stem may be ad- Sure variation. It effects such result by perjustably altered. A set screw 86 is received in threaded engagement at the side of the housing and is adapted to be employed as a stop acting cooperatively with the spring 84 to control the movement of the valve portion in response to any differential in water pressures on the two sides of thediaphragms Preferably this lower valve structure is provided with a socket 61 which is adapted to receive in sliding engagement a guiderod 62 provided on the valve stem 29 in axial alinement therewith. This rod and socket device effects a guiding function for the valves which are movable relatively to each other.

There is thus provided an eflicient governor which assures the automatic maintenance ofa desired speed of rotation of a driven member working under a friction load. While this novel structure is disclosed in its application to wood-pulp grinders 1n the newsprint paper art, it is to be understood that the construction disclosed herein is illustrative but not restrictive and that the same may be modified within the meaning and scope of the claims which follow.

Having thus described my invention what I claim as new, and desire to secure by Letters Patent, is:

1. Means for the automatic maintenance of any desired uniform speed of rotation of a driven member working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a valve movable to control the ressure under which said fluid is supplie a rotatory element actuated by said driven member, and fluid means co-operable with said element to control valve movement whereby said uniform speed of rotation is automatically maintained.

2. Means for the automatic maintenance of any desired uniform speed of rotation of a driven member working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a valve movable to control thepressure under which said fluid is supplied, elastic means straining to move said valve in one direction, a rotatory element actuated by said driven member, and fluid means co-operable with said element straining to move said valve in the opposite direction whereby said uniform speed of rotation is automatically maintained.

3. Means for the automatic maintenance of any desired uniform speed of rotation of a driven member working under a friction load produced by fluid pressure including, apass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, elastic means straining to move said valve in one direction, means for adjusting the elastic means whereby the straining effort of said elastic means to move the valve in such di* rection is adjustably altered, a rotatory ele ment actuated by said driven member, and fluid means co-operable with said element straining to move said valve in the opposite direction whereby said uniform speed of rotation is automatically maintained.

4. Means'for the automatic maintenance of any desired uniform speed of rotation of a driven member working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, elastic means straining to move said valve in one direction, fluid means straining to move said valve in an opposite direction, and a rotatory element actuated by said driven member and adapted to vary the straining effort of said fluid means in proportion to the speed of rotation of said driven member whereby said uniform speed of rotation is automatically maintained.

5. Means for the automatic maintenance of any desired uniform speed of rotation of a driven member working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, elastic means straining to move said valve in one direction, fluid means straining to move said valve in an opposite direction, a pressure chamber for said fluid means, means on said valve projecting into said pressure chamber whereby variations in the straining effort of said fluid means in said chamber produce valve movement in said opposite direction, and a rotatory element actuated by said drive-n member and adapted to vary the straining effort of said fluid means in said chamber in proportion to the speed of rotation of said driven member whereby said uniform speed of rotation is automatically maintained.

6. Means for the automatic maintenance of any desired uniform speed of rotation of a driven member Working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, a pressure chamber, a movable partition in said chamber, means connecting said valve with said partition to cause the valve to move therewith, elastic means straining to move said partition in one direction, fluid means strain- 'ing to move said partition in an opposite diof a desired speed of rotation of a driven member working under a friction load produced by' fluid pressure including, an instrumentality having normal movement forcibly to maintain objects in engagement with said working member and having abnormal movement upon travel to and from maintaining position, a pass adapted to supply fluid under pressure, a valve co-operating with said driven member to control the pressure under which said fluid is supplied to said instrumentality to cause said normal movement thereof, and a second valve operable to permit increased flow of fluid under pressure tothe instrumentality, said increased flow being caused by abnormal movement thereof, whereby variations in pressure at said instrumentality which normally would result from variations in fluid flow through said pass are prevented.

8. Means for the automatic maintenance of a desired speed of rotation. of a driven member working under a friction load produced by fluid pressure including, a plurality of instrumentalities each having normal movement forcibly to maintain objects in engagement with said working member and having abnormal movement upon travel to and from maintaining posit-ion, a pass adapted to supply fluid under pressure, a .valve co-operable with said driven member to control the pressure under which said fluid is supplied to each instrumentality to cause normal movement thereof, and a second valve operable to permit increased flow of fluid under pressure to each instrumentality caused by abnormal movement thereof, whereby variations in pressure which normally would result from variations in fluid flow through said pass are prevented.

9. Means for the automatic maintenance of a desired speed of rotation, of a driven member working under a friction load produced by fluid pressure including, a pass adapted to supply fluid under pressure, a driven shaft, a plurality of rotatably driven working members on said shaft, a plurality of instrumentalities for each driven Working member, each instrumentality having normal movement forcibly to maintain objects in engagement with said working memher, and having abnormal movement upon travel to and from maintaining position, a valve co-operable with said driven shaft to control the pressure under which said fluid is supplied to each of said instrumentalities to cause normal movements thereof, and a by fluid pressure, including, apass adapted v to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, said ass having a main section and a gradua ly contracted section adapted to transform a portion of the fluid pressure into fluid velocity, a pressure compartment, a movable partltion therein, a passage connecting the contracted section and the compartment on one side of the partition, a passage connecting the main section and the compartment on the other side of the partition, and means connecting said partition to the Valve whereby motion of said valve is produced by variations in fluid flow through said supply pass.

11. Means for the automatic maintenance of a desired speed of rotation of a driven member Working under a friction load produced by fluid pressure, including, a pass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, said pass having a main section and a gradually contracted section adapted to transform a portion of the fluid pressure head into fluid velocity head, a pressure compartment, a movable partition therein, a passage connecting the contracted section and the compartment on one side of the partition, a

passage connecting the main section and the compartment on the other side of the partition, means connecting said partition to the vave whereby motion of said valve is produced by variations in fluid flow through said supply pass, and means to adjust 'the movement of said valve.

12. Means for the automatic maintenance of a desired speed of rotation of a" driven member working under a-friction load produced by fluid pressure, including,--a--p ass adapted to supply 'fluidundfpressur;

means actuated by the-Lirotation ofthe driven member to control pressure in asaid'giass,

and a complementary means actuate A pressure therein. I g

13. Means for the automatic maintenance fluid flow through said pa's's toicontrol the' of a desired speed of rotation of a driven member working under affriction load pro duced by fluid pressure including, a twopart supply of fluid under pressure to produce said load, a by-pass to supply one part thereof, and a pass to supply the other part,

and means automatically to control the part supplied through said pass proportionately to the speed of rotation of said driven mem ber. I

14. Means for the automatic maintenance of a desired speed of rotation of a driven member working under a friction load produced by fluid pressure including, a twopart supply of fluid under pressure to produce said load, a by-pass to supply'a substantially constant part thereof, and a pass to supply variably the other part thereof, and means automatically to vary the part supplied through said pass proportionately to the speed of rotation of said driven member.

15. Means for the automatic maintenance of any desired uniform speed of rotation, of a driven member working under a friction load produced by fluid pressure including, a two-part supply of fluid under pressure to produce said load, a by-pass to supply one part thereof, and a pass to supply the other part, and means automatically to control the part supplied through said pass so as to maintain any desired speed of rotation of the driven member.

16. Means for the automatic maintenance of any desired uniform speed of rotation, of a driven member working under a frlction load produced by fluid pressure, including, a pass adapted to supply fluid under pressure, a valve movable to control the pressure under which said fluid is supplied, elastic means straining to move said valve in one direction, a rotatory element actuated by said driven member, fluid means cooperable with said element straining to move said valve in the opposite direction, whereby said uniform speed of rotation is automatically maintained, and said elastic means being adapted upon non-actuation of said rotatory element to move the valve to passopening position whereby rotation of the driven member is stopped.

17. Means for the automatic maintenance of a desired speed of rotation of a driven member Working under a friction load produced by fluid pressure including, an instrumentality having normal movement forcibly to maintain objects in engagement with said working member and having abnormal movement upon travel to and from maintaining position, a pass adapted to supply fluid under pressure, a valve co-operating with said driven member to control the pressure under which said fluid is supplied to said instrumentality to cause said normal movement thereof, and a second valve operable to permit increased flow of fluid under pressure to the instrumentality, said pass having a portion shaped to provide a Venturi tube, a pressure chamber, a partition movable in said chamber and connected to said second valve, passages leading to the pressure chamber at opposite sides of the partition and from different portions of the .Venturi tube whereby said second valve operates to permit increased flow of fluid under pressure to the instrumentality upon abnormal movement of said instrumentality wherebyvariations in pressure at said instrumentality which normally would result from variations in fluid flow through said pass are prevented.

In witness whereof, I have hereunto set my hand this 17th day of March 1920.

ADOLPH F. MEYER. 

